1. Field of the Invention
The present invention relates to a meander line antenna used for mobile communications and in local area network (LAN).
2. Description of the Related Art
FIG. 6 shows a monopole antenna 50, which is a conventional line-shaped antenna. The monopole antenna 50 has one conductor 52 almost upright against a ground surface 51 in the air (relative dielectric constant .di-elect cons.=1, relative magnetic permeability .mu.=1). A power source V is connected to one end 53 of the conductor 52, and the other end 54 is free.
Since the conductor of a line-shaped antenna, typical of which is the above conventional monopole antenna, exists in the air, the dimensions thereof are large. Assuming that the wavelength of a signal in a vacuum is .lambda..sub.0, for example, the conductor of a monopole antenna is required to have a length of .lambda..sub.0 /4. When the resonant frequency is 1.0 GHz or less, the conductor of a monopole antenna needs to be at least about 7.5 cm long.
Therefore, it is difficult to use a monopole antenna in a case in which a compact antenna is required, especially in low-frequency mobile communications.